Resolution enhancement of image intensification systems

ABSTRACT

An image intensification system utilizing an image intensifier having a channel type electron multiplier. The light input to the intensifier is oscillated vertically up and down by an electrically active double refracting input crystal. An oscillator provides an A.C. voltage for the crystal. The light output of the intensifier is unscrambled by another such crystal at the intensifier output, which crystal also receives an input from the oscillator. That is, the intensifier oscillating output image is made to appear stationary by operation of the output crystal. Another embodiment employs a vidicon at the intensifier output, the vidicon vertical sweep being amplitude modulated in synchronism with the oscillator output. Although completely unexpected, the intensifier resolution is substantially improved.

United States Patent [191 Reif [ 1 Jan. 9, 1973 1541 RESOLUTIONENHANCEMENT OF IMAGE INTENSIFICATION SYSTEMS [75] Inventor: PhilipGeorge Reit', Chatsworth,

Calif.

[73] Assignee: International Telephone and Telegraph Corporation, NewYork, NY.

OTHER PUBLICATIONS Keller et al, Induced Birefringent Storage Display,IBM Technical Disclosure Bulletin, Vol. 12, No. 2, July 1969, p. 333

Primary ExaminerArchie R. Borchelt Assistant Examiner-T. N. GrigsbyAttorney-C. Cornell Remsen, Jr. et al.

[57] ABSTRACT An image intensification system utilizing an imageintensifier having a channel type electron multiplier. The light inputto the intensifier is oscillated vertically up and down by anelectrically active double refracting input crystal. An oscillatorprovides an A.C. voltage for the crystal. The light output of theintensifier is unscrambled by another such crystal at the intensifieroutput, which crystal also receives an input from the oscillator. Thatis, the intensifier oscillating output image is made to appearstationary by operation of the output crystal. Another embodimentemploys a vidicon at the intensifier output, the vidicon vertical sweepbeing amplitude modulated in synchronism with the oscillator output.Although completely unexpected, the intensifier resolution issubstantially improved.

25 Claims, 3 Drawing Figures RESOLUTION ENHANCEMENT OF IMAGEINTENSIFICATION SYSTEMS BACKGROUND OF THE INVENTION This inventionrelates to tubes employing channel type electron multipliers, and moreparticularly, to an image intensification system for producing an imageor image data having an unusually high resolution.

In the past, a system was previously derived to improve the resolutionof an image intensifier employing a channel type electron multiplier.See copending application Ser. No. 797,372 filed .Ian. 30, 1969, by R.K. Orthuber for MULTICOLOR DIRECT VIEW DEVICE. This system includesmeans for oscillating the intensifier. The improvement in resolution inthis case is very substantial and unexpected. However, damage tointensifier component parts is possible. A more rugged and moreexpensive tube can, therefore, be required. Further, reliability can bea problem and the system has all the other complexity, expense, repairand other disadvantages of an electromechanical arrangement which theprior art system incorporates.

SUMMARY OF THE INVENTION In accordance with the system of the presentinvention, the above-described and other disadvantages of the prior artare overcome by connecting the output of an oscillator to input andoutput crystals located at the input, and output, respectively, of animage intensifier, or by employing a vidicon or other device at theintensifier output and modulating the amplitude of at least onedeflection signal in synchronism with the oscillator output.

In either case, the image intensifier is of the type which employs achannel type electron multiplier.

Both crystals need not be employed when a vidicon is used. In any event,all of the crystals may be electrically active double refracting orbirefringent crystals. Such crystals are, by themselves and not in thesystem of the present invention, entirely conventional. Such crystalsand their uses are described in many places in the prior art, one suchplace being in Volumne 9, No. 6, November 1966, IBM Technical DisclosureBulletin. See also copending application Ser. No. 65,614, now U.S. Pat.No. 3,639,684 filed Aug. 20, 1970, by A. M. Levine for FIELD SEQUENTIALLASER SCAN FOR NIGHT COLOR TELEVISION.

In accordance with the present invention, it is an outstanding advantagethat the image intensifier employed in the system of the presentinvention has much improved resolution. Although this is completelyunexpected, it is believed that a mechanism must be at work, whichmechanism may be, in a few respects, similar to that by which resolutionis improved by actually gyrating or moving the intensifier by the meanspreviously described.

It is also substantially unexpected that the linear light oscillation orimage oscillation produced by the input crystals alternately in twoopposite directions would improve resolution.

The above-described and other advantages of the present invention willbe better understood from the following detailed description whenconsidered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which are to beregarded as merely illustrative:

FIG. 1 is a longitudinal sectional view of an image intensificationsystem, partly in elevation, constructed in accordance with the presentinvention; I

FIG. 2 is a transverse sectional view of a channel type electronmultiplier shown in FIG. 1; and

FIG. 3 is a longitudinal elevational view, partly in section, of anotherembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, an evacuatedenvelope is indicated at 10 including a glass cylinder 1 1, and fiberoptics input and output windows 12 and 13, respectively. By themselves,windows 12 and 13 may be entirely conventional as may be all other fiberoptics windows disclosed herein.

A photocathode layer 14 is fixed to the interior surface of window 12. Aphosphor screen layer 15 is fixed to the internal surface of window 13.A channel type electron multiplier 16 is fixed relative to envelope 10inside thereof between and in spaced relation to layers 14 and 15 on theinput and output sides thereof, respectively. A cylinder 17 is fixedrelative to envelope 10 on the left end thereof. Cylinder 17 supports alens 18 at the left end thereof, a polarizer 19 and an electricallyactive double refracting input crystal 20.

Polarizer 19 is located between and spaced from each of lens 18 andcrystal 20.

Crystal 20 is supported in a position which may be in contact withwindow 12.

At the right end of the assembly of FIG. 1, a cylinder 21 is fixedrelative to envelope 10 and carries a crystal 22 which may be or may notbe identical to crystal 20, as desired. Cylinder 21 also supports ananalyzer 23 which may, in fact, be a polarizer, depending upondefinition. That is, for example, analyzer 23 may or may not beprecisely identical to polarizer 19, as desired.

Again, crystal 22 may abut the face of window 13.

Envelope l0 and the structures contained therein may be defined as animage intensifier. The image intensifier may be operated, as isconventional, by a source of potential 24, whereby layer 14 ismaintained at the lowest potential; the potential of an input electrode25 of multiplier 16 is maintained at a potential higher than that oflayer 14; the potential of an output electrode 26 of multiplier 16 ismaintained at a potential higher than that of electrode 25; and layer 15is maintained at a potential higher than that of electrode 26.

An oscillator 27 is provided to operate crystals 20 and 22. Oscillator27 may produce an output signal which is an alternating voltage having asawtooth, a triangular wave, a sine wave or another shape.

Sometimes it may be desirable to adjust the amplitudes of the signalsapplied to crystals 20 and 22, which adjustment may or may not beemployed or provided, as desired. However, as shown in FIG. 1, one ormore potentiometers 28 and 29 may be connected from oscillator 27 toground, if desired. Potentiometer 28 has a winding 30 and a wiper 31.Potentiometer 29 has a winding 32 and a wiper 33. Wiper 31 is connectedto crystal 20, and wiper 33 is connected to crystal 22.

Channel type electron multipliers are old in the art, by themselves. Forexample, see US. Pat. No. 3,541,254. However, the section of FIG. 2shows multiplier 16 in somewhat greater detail. Multiplier 16 has adielectric plate 34 upon which conductive layers are evaporated to formelectrodes 25 and 26. Plate 34 has a multitude of holes 35 extendingcompletely therethrough. Plate 34 thus has cylindrical internal surfaces36 at least partially defining holes 35, surfaces 36 being secondaryemissive.

As shown in FIG. 2, input electrode 25 has holes 37 extending completelytherethrough in registration with holes 35 of plate 34.

Output electrode 26 also has holes 38 which lie in registration with theplate holes 35.

When electrons enter multiplier 16 through holes 37 in input electrode25, such electrons impact the surface 36 near input electrode 25.Secondary electrons are then released. Electron multiplication thenoccurs so that the current output in the vicinity of one outputelectrode hole 38 is a great many times larger than the input currentthrough the corresponding input electrode hole 37.

In the operation of the invention of FIG. 1, oscillator 27, for example,applies a sine wave signal to crystal 20. Crystal 20, at all times,passes an image to window 12 which is an image of the field of view.However, the application of the output signal of oscillator 27 tocrystal 20 causes the image on window 12 to be shifted back and forthalternately in two opposite directions.

The frequency of oscillator 27 is by no means critical. The frequency ofoscillator 27 may be, if desired, sufficiently high so as to obtain allsubstantial resolution improvement, if desired. However, it may beconvenient to keep the frequency of oscillator 27 relatively low. Nosubstantial disadvantages are attendant upon the use of a low frequencyoscillator 27. Since, as will be described, there is a certainsynchronism, the frame rate relative to the naked eye is not important.That is, the frequency of oscillator 27 is wholly independent of thepersistence of vision. However, at a relatively low oscillatorfrequency, it will be understood that electron transit time problems donot exist. If the oscillator frequency is too low, insufficientresolution improvement may result. A typical, although not critical,frequency for oscillator 27 might be 16 Hz. However, a range lower orhigher than I Hz to 20 Hz is possible.

Note will be taken that in order for crystal 20 to be operated inamanner to shift the image on window 12 coherently, light must belinearly polarized by polarizer 19 when crystal 20, for example,oscillates the image on window 12 vertically up and down. Similarly,polarizer 23 must be positioned so as to provide polarized lightpolarized in the same direction as light emitted from the right side ofpolarizer 19.

OPERATION OF THE EMBODIMENT OF FIG. 1

In the operation of the system of FIG. 1, polarizer 19 polarizes thelight output of lens 18. Oscillator 27 then causes the image on window12 provided through crystal 20 to oscillate up and down. Sincemultiplier 16 is fixed relative to the moving image on window 12, it istrue that current multiplication takes place in different holes 35 forthe same image spot or elemental area, but the result is only that theimage produced on the right face of window 13 also oscillates. Phosphorlayer 15, which is a luminescent screen, contains phosphors which aresufficiently fast to follow the motion produced at the frequency ofoscillator 27.

Crystal 22 is controlled so as to effectively follow the moving image onthe right face of window 13. The result then is, at the right handsurface of polarizer 23, a stationary image of improved resolution.

THE ALTERNATIVE EMBODIMENT OF FIG. 3

All the structures shown in FIG. 1 may be employed in the embodiment ofFIG. 3 with the exception of crystal 22 and polarizer 23. Parts 10' to34, inclusive, in FIG. 3 may be identical to parts 10 to 34, inclusive,respectively, except for parts 22 and 23, as aforesaid. However, thereis one other exception. Since crystal 22 is missing in FIG. 3,potentiometer wiper 33' in FIG. 3 is not connected to any crystal,whereas potentiometer wiper 33 in FIG. 1 is connected to crystal 22. InFIG. 3, a number of other structures are shown in addition to thestructure of FIG. 1.

In FIG. 3, a vidicon is shown at 39 including an evacuated envelope 40closedat its left end by a fiber optics window 41. The left end ofenvelope 40 including window 41 abuts window 13. A photoconductive layer42 is fixed to window 41 inside envelope 40. Envelope 40 is fixedrelative to cylinder 21'. Layer 4 2 is connected to an output circuit43. Output circuit 43 may be connected to any kind of utilization device44 such as a kinescope for closed circuit television or a televisiontransmitter.

The system of the present invention is by no means limitedto eitherelectrostatic or magnetic deflection of the vidicon electron beam.Although magnetic deflection is most commonly used, electrostaticdeflection has been illustrated as the simplest mode of practicing theinvention.

A main control circuit 45 is connected from tube 39.

Circuit 45 has a sync generator 46. An auxiliary control circuit 47 isconnected from circuit 45 to a vertical deflection plate 48. The othervertical deflection plate 49 is connected to ground.

Tube 39 has horizontal deflection plates 50 and 51. Tube 39 also has anelectron gun 52. Circuit 47 includes a vertical sweep generator 53 andan analog adder 54. Circuit 47 also includes the potentiometer 29', thewiper 33 of which is connected to one input of adder 54. Adder 54 has asecond input from the output of vertical sweep generator 53. The outputof sync generator 46 is connected to the input of vertical sweepgenerator 53. The output of adder 54 is connected to the verticaldeflection plate 48.

OPERATION OF THE EMBODIMENT OF FIG. 3

In the operation of the embodiment of FIG. 3, the image on the left handface of window 12 is oscillated up and down by the control of crystal20' through oscillator 27', as before. An oscillating image then appearson the right hand face of window 13. Light emanating from layer 15' thuspasses through window 13' and still appears as an oscillating image onthe left hand face of vidicon window 41.

Tube 39 may be entirely conventional. However, if auxiliary controlcircuit 47, or some other means were not provided, the video output ofvidicon 39 would represent an oscillating image. Thus, what circuit 47does is to obtain a video output which is exactly the same as it woulddo so if the image displayed on the left hand face of the vidicon window41 were stationary. This is done by modulating the vertical position ofthe electron beam of vidicon 39 in synchronism with the oscillation oftheimage on the left hand face of the vidicon window 41. Modulation isperformed simply by adding to the conventional output of a conventionalvertical sweep generator, a signal which is directly proportional to theoutput voltage of oscillator 27.

From the foregoing, it will be appreciated that vidicon 39 may beentirely conventional. The same is true of circuit 45 including syncgenerator 46, output circuit 43, utilization device 44 and verticalsweep generator 53. However, it is only vertical sweep generator 53, byitself, that is conventional. It is not the connection thereof incircuit 47. The same is true of adder 54 and potentiometer 29.

The phrase means to maintain at a potential is hereby defined for useherein and in the claims to mean source 24, only the conductive leadsconnected from source 24, or neither.

Although oscillation up and down of images has been described in avertical direction, it is to be understood that such oscillation maytake place in any direction as long as the invention is practiced astaught hereinabove.

The phrase electrically active double refracting crystal is herebydefined for use herein and in the claims to mean any device which istransparent to light and will shift the position thereof at the outputfrom that at the input as a function of the magnitude of a signalapplied thereto. Thus, the phrase electrically active double refractingcrystal includes a birefringent crystal.

In FIG. 3, polarizer 19 may be oriented to vertically polarize lightpassing therethrough.

What is claimed is:

1. In an image intensification system, the combination comprising:intensifier means, an evacuated envelope having spaced front and reartransparent windows; a photocathode layer fixed relative to said frontwindow contiguous thereto inside said envelope; a luminescent screenlayer fixed relative to said rear window contiguous thereto inside saidenvelope; a channel type electron multiplier fixed relative to saidenvelope inside thereof between said windows; a first light polarizer;means to support said first polarizer in a position adjacent to saidfront window to polarize light directed theretoward; a second lightpolarizer; means to support said second polarizer in a position adjacentsaid rear window at least a first transparent device, said device beingactuable to shift light passing therethrough in a predetermineddirection an amount which is a function of the magnitude ofa signalapplied thereto; means to support said first device in a positionadjacent to said front window and actuable to shift the position oflight falling on said front window relative to its correspondingposition on the opposite side of said first device; utilization meansfixed relative to said second polarizer to receive the light passingtherethrough which emanates from said rear window; and oscillatorcontrol means connected to said first device and to said utilizationmeans to operate them synchronously, said control means causing saidfirst device to oscillate the image at said rear window via saidintensifier means, said control means synchronous operation of saidutilization means with said first device causing said utilization meansto follow synchronously the said oscillating rear window image.

2. The invention as defined in claim 1, wherein said utilization meansincludes a second transparent device actuable to shift light passingtherethrough an amount which is a function of the magnitude of a signalapplied thereto, and means to support said second device in a positionadjacent to said rear window and actuable to shift the position of lightemanating, a second polarizer fixed relative to said second device onthe side thereof opposite that on which said rear window is positioned,both of said polarizers being positioned to polarize light in the samedirection.

3. The invention as defined in claim 2, wherein said first and seconddevices include electrically active double refracting crystals, saidcontrol means including an oscillator connected to both of said firstand second devices to cause light passing therethrough to be shifted inan oscillatory manner in one of two opposite directions and insynchronism, the amplitudes of the light shifts through said devicesbeing in accordance with the amplitude of the alternating output signalof said oscillator, said oscillator being connected to said first andsecond devices and both of said first and second devices being mountedin a manner such that they shift light passing therethrough insynchronism in the same direction, said second device having a shiftamplitude the same as the image on said luminescent screen layer.

4. The invention as defined in claim 3, wherein said first device ispositioned contiguous to said .first window, said first device beingpositioned between said first polarizer and said front window, saidfirst polarizer being spaced from said first device, lens means, meansto support said lens means adjacent said first polarizer 'on the sidethereof opposite the side on which said first device is positioned, saidsecond device being positioned contiguous to said rear window, saidsecond device being positioned between said rear window and said secondpolarizer.

5. The invention as defined in claim 4, wherein said multiplier includesa dielectric plate having holes therethrough extending approximately ina direction from said front window to said rear window, said platehaving internal surfaces at least partially defining said holes, saidinternal surfaces being secondary emissive, a front conductive electrodefixed relative to said plate on the front window side thereof, a rearconductive electrode fixed relative to said plate on the rear windowside thereof, both of said electrodes having holes therethrough whichlie in registration with said plate holes.

6. The invention as defined in claim 5, wherein said electrodes arelayers evaporated onto opposite sides of said plate, and means to applysuccessively higher potentials to said layers, said front electrodepotential being greater than that of said photocathode layer and lessthan that of said rear electrode potential, said luminescent screenlayer having a potential greater than that of said rear electrode.

7. The invention as defined in claim 1, wherein said utilization meansincludes an image tube having scanning means connected from said controlmeans to modulate the scan thereof in synchronism with the shift oflight produced by actuation of said first device and to compensate forthe image movement on said luminescent screen produced by said firstdevice actuation.

8. The invention as defined in claim 7, wherein said image tube is avidicon having a main control circuit connected therefrom, said maincontrol circuit including a sync generator, said control means includingan oscillator having its output connected to said first device, and anauxiliary control circuit connected from said oscillator output and fromthe output of said sync generator, said vidicon having means to producean electron beam and'vertical and horizontal deflection means to deflectsaid beam, said auxiliary control circuit including means to supply asignal to at least one of said deflection means to cause modulation ofthe position of said beam in synchronism with and in the same directionand amplitude as the shift in the image on said luminescent screen layerproduced by the shift of light through said first device, said shift oflight through said first device being oscillatory in nature in one oftwo opposite directions and of an amplitude which is a function of theamplitude of the alternating output signal of said oscillator.

9. The invention as defined in claim 8, wherein said first deviceincludes an electrically active double refracting crystal.

10. The invention as defined in claim 9, wherein said auxiliary controlcircuit means includes a vertical sweep generator connected from saidsync generator, and an adder connected from said vertical sweepgenerator and said oscillator to said vertical deflection means, saidoscillator being connected to said first device and said first devicebeing positioned in a manner to shift light in a vertical direction.

11. The invention as defined in claim 10, wherein said first device ispositioned contiguous to said first window, said first device beingpositioned between said first polarizer and said front window, saidfirst polarizer being spaced from said first device, lens means, meansto support said lens means adjacent said first polarizer on the sidethereof opposite the side on which said first device is positioned.-

12. The invention as defined in claim 11, wherein said multiplierincludes a dielectric plate having holes therethrough extendingapproximately in a direction from said front window to said rear window,said plate having internal surfaces at least partially defining saidholes, said internal surfaces being secondary emissive, a frontconductive electrode fixed relative to said plate on the front windowside thereof, a rear conductive electrode fixed relative to saidplate onthe rear window side thereof, both of said electrodes having holestherethrough which lie in registration with said plate holes.

13. The invention as defined in claim 12, wherein said electrodes arelayers evaporated onto opposite sides of said plate, and means to applysuccessively higher potentials to said layers, said front electrodepotential being greater than that of saidphotocathode layer and lessthan that of said rear electrode potential, said luminescent screenlayer having a potential greater than that of said rear electrode.

14. The invention as defined in claim 1, wherein said windows are bothfiber optics windows.

15. The invention as defined in claim 3, wherein both of said windowsare fiber optics windows.

16. The invention as defined in claim 7, wherein both of said windowsare fiber optics windows, said image tube including an evacuatedenvelope having a fiber optics image receiving window positionedadjacent said rear window outside said envelope.

17. The invention as defined in claim 16, wherein said image tube windowis positioned contiguous to said rear window.

18. The invention as defined in claim 8, wherein both of said windowsare fiber optics windows, said image tube including an evacuatedenvelope having a fiber optics image receiving window positionedadjacent said rear window outside said envelope.

19. The invention as defined in claim 18, wherein said second image tubewindow is positioned contiguous to said rear window.

20. In an image intensification system, the com bination comprising: anevacuated envelope having a light input window and a light outputwindow; input means including an input device mounted in front of saidinput window and adjacent thereto and actuable to oscillate a beam oflight thereon; an oscillator; and output means mounted to the rear ofsaid output window and adjacent thereto, said oscillator being connectedto said device and said input device being connected and positioned in amanner such that the image on said input window produced by the passageof light to said input window oscillates in synchronism with the outputsignal of said oscillator, the oscillation of the image on said inputwindow causing the image on said output window to oscillatesynchronously therewith, said output means including compensation meansconnected from said oscillator to follow said output window image insynchronism therewith in a manner to unscramble the same and to producea sensed output as though said output window image were stationary.

21. The invention as defined in claim 20, wherein said compensationmeans is an output device mounted to the rear of said output window andadjacent thereto and actuable to oscillate a beam of light emanatingtherefrom, and a channel type electron multiplier fixed relative to saidenvelope inside thereof between said windows.

22. The invention as defined in claim 21, wherein each of said devicesincludes a birefringent crystal.

23. The invention as defined in claim 20, wherein said compensationmeans includes a vidicon including an evacuated envelope having a lightinput window, a photoconductive layer fixed relative to said vidiconenvelope inside thereof contiguous to said window thereof, said vidiconenvelope window being fixed adjacent said output window, an electron gunfixed relative to said vidicon envelope inside thereof to produce anelectron beam to scan said photoconductive layer, a main control circuitincluding a sync generator, a vertical sweep generator connected fromsaid sync generator, vertical sweep deflection means for said vidicon,

24. The invention as defined in claim 23, including a channel typeelectron multiplier fixed relative to said envelope inside thereofbetween said windows.

25. The invention as defined in claim 23, wherein said input deviceincludes a birefringent crystal.

1. In an image intensification system, the combination comprising:intensifier means, an evacuated envelope having spaced front and reartransparent windows; a photocathode layer fixed relative to said frontwindow contiguous thereto inside said envelope; a luminescent screenlayer fixed relative to said rear window contiguous thereto inside saidenvelope; a channel type electron multiplier fixed relative to saidenvelope inside thereof between said windows; a first light polarizer;means to support said first polarizer in a position adjacent to saidfront window to polarize light directed theretoward; a second lightpolarizer; means to support said second polarizer in a position adjacentsaid rear window at least a first transparent device, said device beingactuable to shift light passing therethrough in a predetermineddirection an amount which is a function of the magnitude of a signalapplied thereto; means to support said first device in a positionadjacent to said front window and actuable to shift the position oflight falling on said front window relative to its correspondingposition on the opposite side of said first device; utilization meansfixed relative to said second polarizer to receive the light passingtherethrough which emanates from said rear window; and oscillatorcontrol means connected to said first device and to said utilizationmeans to operate them synchronously, said control means causing saidfirst device to oscillate the image at said rear window via saidintensifier means, said control means synchronous operation of saidutilization means with said first device causing said utilization meansto follow synchronously the said oscillating rear window image.
 2. Theinvention as defined in claim 1, wherein said utilization means includesa second transparent device actuable to shift light passing therethroughan amount which is a function of the magnitude of a signal appliedthereto, and means to support said second device in a position adjacentto said rear window and actuable to shift the position of lightemanating, a second polarizer fixed relative to said second device onthe side thereof opposite that on which said rear window is positioned,both of said polarizers being positioned to polarize light in the samedirection.
 3. The invention as defined in claim 2, wherein said firstand second devices include electrically active double refractingcrystals, said control means including an oscillator connected to bothof said first and second devices to cause light passing therethrough tobe shifted in an oscillatory manner in one of two opposite directionsand in synchronism, the amplitudes of the light shifts through saiddevices being in accordance with the amplitude of the alternating outputsignal of said oscillator, said oscillator being connected to said firstand second devices and both of said first and second devices beingmounted in a manner such that they shift light passing therethrough insynchronism in the same direction, said second device having a shiftamplitude the same as the image on said luminescent screen layer.
 4. Theinvention as defined in claim 3, wherein said first device is positionedcontiguous to said first window, said first device being positionedbetween said first polarizer and said front window, said first polarizerbeing spaced from said first device, lens means, means to support saidlens means adjacent said first polarizer on the side thereof oppositethe side on which said first device is positioned, said second devicebeing positioned contiguous to said rear window, said second devicebeing positioned between said rear window and said second polarizer. 5.The invention as defined in claim 4, wherein said multiplier includes adielectric plate having holes therethrough extending approximately in adirection from said front window to said rear window, said plate havinginternal surfaces at least partially defining said holes, said internalsurfaces being secondary emissive, a front conductive electrode fixedrelative to said plate on the front window side thereof, a rearconductive electrode fixed relative to said plate on the rear windowside thereof, both of said electrodes having holes therethrough whichlie in registration with said plate holes.
 6. The invention as definedin claim 5, wherein said electrodes are layers evaporated onto oppositesides of said plate, and means to apply successively higher potentialsto said layers, said front electrode potential being greater than thatof said photocathode layer and less than that of said rear electrodepotential, said luminescent screen layer having a potential greater thanthat of said rear electrode.
 7. The invention as defined in claim 1,wherein said utilization means includes an image tube having scanningmeans connected from said control means to modulate the scan thereof insynchronism with the shift of light produced by actuation of said firstdevice and to compensate for the image movement on said luminescentscreen produced by said first device actuation.
 8. The invention asdefined in claim 7, wherein said image tube is a vidicon having a maincontrol circuit connected therefrom, said main control circuit includinga sync generator, said control means including an oscillator having itsoutput connected to said first device, and an auxiliary control circuitconnected from said oscillator output and from the output of said syncgenerator, said vidicon having means to produce an electron beam andvertical and horizontal deflection means to deflect said beam, saidauxiliary control circuit including means to supply a signal to at leastone of said deflection means to cause modulation of the position of saidbeam in synchronism with and in the same direction and amplitude as theshift in the image on said luminescent screen layer produced by theshift of light through said first device, said shift of light throughsaid first device being oscillatory in nature in one of two oppositedirections and of an amplitude which is a function of the amplitude ofthe alternating output signal of said oscillator.
 9. The invention asdefined in claim 8, wherein said first device includes an electricallyactive double refracting crystal.
 10. The invention as defined in claim9, wherein said auxiliary control circuit means includes a verticalsweep generator connected from said sync generator, and an adderconnected from said vertical sweep generator and said oscillator to saidvertical deflection means, said oscillator being connected to said firstdevice and said first device being positioned in a manner to shift lightin a vertical direction.
 11. The invention as defined in claim 10,wherein said first device is positioned contiguous to said first window,said first device being positioned between said first polarizer and saidfront window, said first polarizer being spaced from said first device,lens means, means to support said lens means adjacent said firstpolarizer on the side thereof opposite the side on which said firstdevice is positioned.
 12. The invention as defined in claim 11, whereinsaid multiplier includes a dielectric plate having holes therethroughextending approximately in a direction from said front window to saidrear window, said plate having internal surfaces at least partiallydefining said holes, said internal surfaces being secondary emissive, afront conductive electrode fixEd relative to said plate on the frontwindow side thereof, a rear conductive electrode fixed relative to saidplate on the rear window side thereof, both of said electrodes havingholes therethrough which lie in registration with said plate holes. 13.The invention as defined in claim 12, wherein said electrodes are layersevaporated onto opposite sides of said plate, and means to applysuccessively higher potentials to said layers, said front electrodepotential being greater than that of said photocathode layer and lessthan that of said rear electrode potential, said luminescent screenlayer having a potential greater than that of said rear electrode. 14.The invention as defined in claim 1, wherein said windows are both fiberoptics windows.
 15. The invention as defined in claim 3, wherein both ofsaid windows are fiber optics windows.
 16. The invention as defined inclaim 7, wherein both of said windows are fiber optics windows, saidimage tube including an evacuated envelope having a fiber optics imagereceiving window positioned adjacent said rear window outside saidenvelope.
 17. The invention as defined in claim 16, wherein said imagetube window is positioned contiguous to said rear window.
 18. Theinvention as defined in claim 8, wherein both of said windows are fiberoptics windows, said image tube including an evacuated envelope having afiber optics image receiving window positioned adjacent said rear windowoutside said envelope.
 19. The invention as defined in claim 18, whereinsaid second image tube window is positioned contiguous to said rearwindow.
 20. In an image intensification system, the combinationcomprising: an evacuated envelope having a light input window and alight output window; input means including an input device mounted infront of said input window and adjacent thereto and actuable tooscillate a beam of light thereon; an oscillator; and output meansmounted to the rear of said output window and adjacent thereto, saidoscillator being connected to said device and said input device beingconnected and positioned in a manner such that the image on said inputwindow produced by the passage of light to said input window oscillatesin synchronism with the output signal of said oscillator, theoscillation of the image on said input window causing the image on saidoutput window to oscillate synchronously therewith, said output meansincluding compensation means connected from said oscillator to followsaid output window image in synchronism therewith in a manner tounscramble the same and to produce a sensed output as though said outputwindow image were stationary.
 21. The invention as defined in claim 20,wherein said compensation means is an output device mounted to the rearof said output window and adjacent thereto and actuable to oscillate abeam of light emanating therefrom, and a channel type electronmultiplier fixed relative to said envelope inside thereof between saidwindows.
 22. The invention as defined in claim 21, wherein each of saiddevices includes a birefringent crystal.
 23. The invention as defined inclaim 20, wherein said compensation means includes a vidicon includingan evacuated envelope having a light input window, a photoconductivelayer fixed relative to said vidicon envelope inside thereof contiguousto said window thereof, said vidicon envelope window being fixedadjacent said output window, an electron gun fixed relative to saidvidicon envelope inside thereof to produce an electron beam to scan saidphotoconductive layer, a main control circuit including a syncgenerator, a vertical sweep generator connected from said syncgenerator, vertical sweep deflection means for said vidicon, and meansconnected from said oscillator and said vertical sweep generator to saidvertical sweep deflection means to oscillate said electron beamvertically up and down in synchronism with the oscillation of the imageon said input window, said input device being actuated to oscillate theimage on said inpuT window vertically up and down.
 24. The invention asdefined in claim 23, including a channel type electron multiplier fixedrelative to said envelope inside thereof between said windows.
 25. Theinvention as defined in claim 23, wherein said input device includes abirefringent crystal.